Traditional shutters are basically designed having a rectangular frame, and plurality of shutter blades pivotally mounted in a generally horizontal fashion extending across the frame, and being swingable between a closed and opened position.
Typically, such shutter blades are controlled and moved by means of a control pull bar. In the past, such control pull bars have usually been mounted centrally down the centre of the blades, and are simply linked to the blades by pivotal connections, so that all of the blades may be pivoted between open and closed positions by a single movement.
This basic design may have been in use for hundreds of years or more. However, there are certain disadvantages. In the first place, the location of the pull bar is somewhat unsightly, since when the shutter blades are swung open the pull bar is positioned in such a way that it extends down the centre of the opening.
In addition, such pull bars may have been suitable for construction where shutter blades were made of wood, but are not as suitable for use where shutter blades are made of thermo-plastic material.
The tendency, at the present time, is to manufacture such shutters with extruded thermo plastic side and end frames, and extruded thermo plastic blades. The extruded thermo plastic blades are hollow, and are cut to a predetermined length. Each end of the blade is provided with a plug end member which plugs into the end of the blade. The plug end members are formed with pivot axles which fit into holes in the side frames.
For this type of shutter, attaching a pull bar centrally of the shutter blades means that each individual shutter blade must have an opening cut in it, and some form of plug in fixture must be inserted into each blade.
Another factor in the manufacture of such shutters is that the opening which the shutters must fill, will vary from one house to another, and from one window or one door to another. In the past, shutters were made with blades having a pre-set fixed spacing between them. The shutter frames were made with relatively wide sections of material, usually wood, and in order to fit the shutter to a particular space, it was customary to cut portions away from either the top or the bottom or both of the shutter frames.
This might result in the installation of shutters which had an appearance which varied from one shutter to another, and in which the shutter blades themselves would not necessarily be aligned all the way across a window or door opening.
A few designs have been produced in which the shutter blades are provided with a pull bar at one end, but again, the location of the pull bar at the end has usually required the use of several components for connecting with each blade which results in an uneconomical construction, and in addition a design which may result in failure in one a the plurality of parts.
An additional factor in the design of such shutters is the tendency of the shutter blades to either swing shut or swing open, in an uncontrolled fashion, especially in drafts or in winds.
Preferably some form of friction or braking mechanism will be provided so as to control the movement of the shutter blades, so that once adjusted they will hold still in a predetermined desired location.